This invention relates to a system and method for braking a towed conveyance and more particularly, to a system and method for braking a towed conveyance such as an automotive vehicle or trailer which provides improved braking stability, efficiency and performance.
Automotive vehicles are often used to tow or haul conveyances such as other automotive vehicles, trailers, motorcycles, boats, and other items. Vehicles and trailers that are towed by a car or truck often represent a relatively large towing load and can become unstable and/or cause situations that frustrate the driver or operator of the towing vehicle.
Particularly, on downgrades, the vehicle or trailer may tend to roll faster than the towing vehicle. In these types of situations, a trailer or vehicle may significantly encumber the braking system of the towing vehicle. For example and without limitation, the towed vehicle may undesirably and significantly lengthen braking distance and may cause significant and premature wear to the brakes of the towing vehicle. Moreover, the towed trailer or vehicle may further undesirably swing to one side or the other due to the geometry of the single point hitch.
Various efforts and systems have been implemented to correct the foregoing conditions. For example and without limitation, some experienced drivers learn to sense or anticipate these conditions and correct these conditions with the steering wheel and/or by adding stabilizing bars to prevent swinging of the towed trailer or vehicle. While such driver-performed maneuvers may be effective to reduce swinging under certain conditions, these maneuvers cannot significantly reduce braking distance or wear to the towing vehicle""s braking system.
Other efforts include trailer brakes which may be installed on a trailer and which are particularly effective in straightening and stabilizing the path of the trailer. For example, a surge type braking system can be installed on a trailer which hydraulically or mechanically actuates trailer brakes in response to pressure on the tow xe2x80x9cballxe2x80x9d or hitch. Other systems include electrically actuated braking systems which are installed on trailers. However, these systems and methods are adapted for use only with trailers and cannot be used with other automotive vehicles that may be desirably towed. Moreover, these systems and methods are energy inefficient and cause excessive wear to the trailer brakes.
There is therefore a need for a system and method for braking a towed conveyance which overcomes the drawbacks of prior systems, methods, and strategies.
It is a first object of the invention to provide a system and method for braking a towed conveyance which overcomes at least some of the previously delineated drawbacks of prior systems, methods and strategies.
It is a second object of the invention to provide a system and method for braking a towed vehicle which utilizes the towed vehicle""s electrical braking, traction control and/or stability system(s) to improve braking stability, efficiency and characteristics.
It is a third object of the invention to provide a system and method for braking a towed conveyance, such as a trailer, which utilizes at least one electric motor/generator to selectively provide braking torque to the conveyance, thereby conserving energy and providing an auxiliary power source in the conveyance.
It is a fourth object of the invention to provide a system and method for braking a towed trailer which utilizes a yaw sensor to detect excessive trailer yaw rate and which activates an electric motor/generator in response to such a detection, effective to provide a braking torque to the trailer, thereby stabilizing the trailer.
According to a first aspect of the present invention, a method is provided for braking a first vehicle having a first braking system which is being towed by a second vehicle having a second electronic braking system. The method includes the steps of communicatively coupling said first braking system to said second braking system; and communicating a braking signal from said second braking system to said first braking system, said braking signal being effective to activate said first braking system and to cause said first braking system to provide a braking force to said first vehicle.
According to a second aspect of the present invention, a system is provided for braking a trailer which includes an axle assembly and which is being towed by a vehicle. The system includes at least one electric machine which is coupled to said axle assembly; a sensor which is effective to measure an attribute of said trailer and to generate a first signal representing said measured attribute; and a controller which is communicatively coupled to said at least one electric machine and said sensor, said controller being effective to receive said first signal and, based upon said first signal, to selectively communicate a second signal to said at least one electric machine, said second signal being effective to cause said at least one electric machine to apply a regenerative braking torque to said axle assembly, thereby braking said trailer and generating electrical energy.
These and other features, aspects, and advantages of the invention will become apparent by reading the following specification and by reference to the following drawings.